plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/dom/FirstOrderOperationCallExpression.java

/*********************************************************************
* Copyright (c) 2008-2018 The University of York.
*
* This program and the accompanying materials are made
* available under the terms of the Eclipse Public License 2.0
* which is available at https://www.eclipse.org/legal/epl-2.0/
*
* SPDX-License-Identifier: EPL-2.0
**********************************************************************/
package org.eclipse.epsilon.eol.dom;

import java.util.ArrayList;
import java.util.List;
import org.eclipse.epsilon.common.module.IModule;
import org.eclipse.epsilon.common.module.ModuleElement;
import org.eclipse.epsilon.common.parse.AST;
import org.eclipse.epsilon.common.util.StringUtil;
import org.eclipse.epsilon.eol.compile.context.IEolCompilationContext;
import org.eclipse.epsilon.eol.exceptions.EolIllegalOperationException;
import org.eclipse.epsilon.eol.exceptions.EolNullPointerException;
import org.eclipse.epsilon.eol.exceptions.EolRuntimeException;
import org.eclipse.epsilon.eol.execute.context.FrameType;
import org.eclipse.epsilon.eol.execute.context.IEolContext;
import org.eclipse.epsilon.eol.execute.operations.AbstractOperation;
import org.eclipse.epsilon.eol.execute.operations.declarative.*;
import org.eclipse.epsilon.eol.models.IModel;
import org.eclipse.epsilon.eol.parse.EolParser;
import org.eclipse.epsilon.eol.types.*;

public class FirstOrderOperationCallExpression extends FeatureCallExpression {
	
	protected List<Parameter> parameters = new ArrayList<>(2);
	protected List<Expression> expressions = new ArrayList<>(3);
	
	public FirstOrderOperationCallExpression() {}
	
	public FirstOrderOperationCallExpression(Expression targetExpression, NameExpression nameExpression, Parameter parameter, Expression lambdaExpression) {
		this.targetExpression = targetExpression;
		this.nameExpression = nameExpression;
		this.parameters.add(parameter);
		this.expressions.add(lambdaExpression);
	}
	
	@Override
	public void build(AST cst, IModule module) {
		super.build(cst, module);
		
		AST lambdaParamsContainer, exprAst;
		
		if (cst.getType() != EolParser.NAME && cst.getFirstChild().getType() != EolParser.PARAMLIST) { 
			targetExpression = (Expression) module.createAst(cst.getFirstChild(), this);
			exprAst = cst.getSecondChild();
			nameExpression = (NameExpression) module.createAst(exprAst, this);
		}
		else {
			nameExpression = new NameExpression(cst.getText());
			nameExpression.setRegion(cst.getRegion());
			nameExpression.setUri(cst.getUri());
			nameExpression.setModule(cst.getModule());
			exprAst = cst;
		}

		lambdaParamsContainer = exprAst != null ? exprAst.getFirstChild() : null;
		
		if (lambdaParamsContainer != null && lambdaParamsContainer.getType() == EolParser.PARAMLIST) {
			for (AST ast : lambdaParamsContainer.getChildren()) {
				parameters.add((Parameter) module.createAst(ast, this));
			}
		}
		
		if (exprAst != null) for (AST ast : exprAst.getChildren()) {
			if (parameters.isEmpty() || ast != lambdaParamsContainer) {
				ModuleElement resolved = module.createAst(ast, this);
				if (resolved instanceof Expression) {
					expressions.add((Expression) resolved);
				}
			}
		}
	}
	
	@Override
	public Object execute(IEolContext context) throws EolRuntimeException {
		Object target = EolNoType.Instance;
		
		if (targetExpression != null) {
			target = context.getExecutorFactory().execute(targetExpression, context);
		}
		else if (!parameters.isEmpty()) {
			EolType iterator = parameters.get(0).getType(context);
			if (iterator instanceof EolModelElementType) {
				target = ((EolModelElementType) iterator).getAllOfKind();
			}
		}
		
		String operationName = nameExpression.getName();
		
		if (target == null) {
			if (isNullSafe()) {
				return null;
			}
			else {
				throw new EolNullPointerException(operationName, targetExpression);
			}
		}
		
		IModel owningModel = context.getModelRepository().getOwningModel(target);
		AbstractOperation operation = getAbstractOperation(target, operationName, owningModel, context);
		
		replaceWithDelegateOperation(SelectBasedOperation.class, SelectOperation.class, operation, target, operationName, owningModel, context);
		replaceWithDelegateOperation(CollectBasedOperation.class, CollectOperation.class, operation, target, operationName, owningModel, context);
		
		return operation.execute(target, nameExpression, parameters, expressions, context);
	}
	
	/**
	 * @since 1.6
	 */
	@Override
	protected AbstractOperation getOperationFromContext(Object target, String name, IModel owningModel, IEolContext context) throws EolIllegalOperationException {
		return context.getOperationFactory().getOptimisedOperation(name, target, owningModel, context);
	}
	
	/**
	 * 
	 * @param <O>
	 * @param <D>
	 * @param delegateClass
	 * @param originalClass
	 * @param operation
	 * @param target
	 * @param originalOpName
	 * @param owningModel
	 * @param context
	 * @throws EolIllegalOperationException
	 * @since 1.6
	 */
	@SuppressWarnings("unchecked")
	private <O extends FirstOrderOperation, D extends DelegateBasedOperation<O>>
		void replaceWithDelegateOperation(Class<D> delegateClass, Class<O> originalClass,
			AbstractOperation operation, Object target, String originalOpName, IModel owningModel, IEolContext context) throws EolIllegalOperationException {
		
		if (delegateClass.isInstance(operation)) {
			D dbo = (D) operation;
			if (dbo.getDelegateOperation().getClass().equals(originalClass)) {
				String delegateOpName = originalClass.getSimpleName();
				delegateOpName = delegateOpName.substring(0, delegateOpName.indexOf("Operation"));
				if (originalOpName.startsWith("parallel") && !StringUtil.firstToLower(delegateOpName).startsWith("parallel")) {
					delegateOpName = "parallel" + delegateOpName;
				}
				else if (originalOpName.startsWith("sequential") && !StringUtil.firstToLower(delegateOpName).startsWith("sequential")) {
					delegateOpName = "sequential" + delegateOpName;
				}
				else {
					delegateOpName = StringUtil.firstToLower(delegateOpName);
				}
				O delegateOp = (O) getAbstractOperation(target, delegateOpName, owningModel, context);
				if (!delegateOp.getClass().equals(originalClass)) {
					dbo.setDelegateOperation(delegateOp);
				}
			}
		}
	}
	
	@Override
	public void compile(IEolCompilationContext context) {
		targetExpression.compile(context);
		EolType contextType = null;
		if (targetExpression.getResolvedType() instanceof EolCollectionType) {
			contextType = ((EolCollectionType) targetExpression.getResolvedType()).getContentType();
		}
		else if (targetExpression.getResolvedType() == EolAnyType.Instance) {
			contextType = targetExpression.getResolvedType();
		}
		
		String name = nameExpression.getName();
		if (name.startsWith("sequential")) name = name.substring(10);
		else if (name.startsWith("parallel")) name = name.substring(8);
		
		if (contextType != null) {
			context.getFrameStack().enterLocal(FrameType.UNPROTECTED, this);
			Parameter parameter = parameters.get(0);
			parameter.compile(context, false);
			if (parameter.isExplicitlyTyped()) {
				//TODO: Check that the type of the parameter is a subtype of the type of the collection
				contextType = parameter.getCompilationType();
			}
			context.getFrameStack().put(parameter.getName(), contextType);
			
			Expression expression = expressions.get(0);
			expression.compile(context);
			
			context.getFrameStack().leaveLocal(this);
			
			if (StringUtil.isOneOf(name, "select", "reject", "rejectOne", "closure", "sortBy")) {
				resolvedType = new EolCollectionType("Sequence", contextType);
			}
			else if (name.equals("selectOne")) {
				resolvedType = contextType;
			}
			else if (name.equals("collect")) {
				resolvedType = new EolCollectionType("Sequence", expression.getResolvedType());
			}
			else if (StringUtil.isOneOf(name, "exists", "forAll", "one", "none", "nMatch, atLeastNMatch, atMostNMatch")) {
				resolvedType = EolPrimitiveType.Boolean;
			}
			else if (name.equals("aggregate")) {
				if (expressions.size() == 2) {
					Expression valueExpression = expressions.get(1);
					valueExpression.compile(context);
					resolvedType = new EolMapType(expression.getResolvedType(), valueExpression.getResolvedType());
				}
				else {
					context.addErrorMarker(nameExpression, "Aggregate requires a key and a value expression");
				}
			}
			else if (name.equals("mapBy")) {
				resolvedType = new EolMapType(expression.getResolvedType(), new EolCollectionType("Sequence", contextType));
			}
			else if (name.equals("sortBy")) {
				resolvedType = new EolCollectionType("Sequence", contextType);
			}
			
			if (StringUtil.isOneOf(name,
				"select", "selectOne", "reject", "rejectOne", "exists", "one", "none", "forAll", "closure") &&
				expression.getResolvedType().isNot(EolPrimitiveType.Boolean)) {
					
				context.addErrorMarker(expression, "Expression should return a Boolean but returns a " + expression.getResolvedType().getName() + " instead");
			}
			
		}
		else {
			context.addErrorMarker(nameExpression, "Operation " + name + " only applies to collections");
		}
	}
	
	public List<Parameter> getParameters() {
		return parameters;
	}
	
	public List<Expression> getExpressions() {
		return expressions;
	}
	
	public void accept(IEolVisitor visitor) {
		visitor.visit(this);
	}
}